Answer: length of B =4.00
Explanation:
for  the vectors A and B and the angle between them as  x.
Magnitude of the sum of A and B is  given as = √(A²+B²+2ABcosx
 where 
Magnitude of A  = 3.00 
Magnitude of the sum of A and B is  5.00
5.00=√(A²+B²+2ABcos90°
5.00= √3² +b² +0
5²= 3² +b² 
25=9+b²
b²= 25-9
b² = 16
b=  √16
b= 4
 
        
             
        
        
        
<span>First, she should put the sample in a test tube and place it in a centrifuge. This would cause the red blood cells to move to the bottom because of their higher density. Next, she would be able to decant the plasma and analyze it separately from the red blood cells.</span>
        
                    
             
        
        
        
- confidence
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Answer:
78 km/h
Explanation:
If I normally drive a 12 hour trip at an average speed of 100 km/h, my destination has a total distance of:
- 100 km/h · 12 h = 1,200 km 
Today, I drive the first 2/3 of the distance at 116 km/h. Let's first calculate what 2/3 of the normal distance is.
I've driven 800 km already. I need to drive 400 km more to reach my final destination. I need to figure out my average speed during this last 1/3 of the distance.
To do this, I first need to calculate how much time I spent driving 116 km/h for the past 800 km.
- 116 km/1 h = 800 km/? h
- 800 = 116 · ?
- ? = 800/116 
- ? = 6.89655172 
I spent 6.89655172 hours driving during the first 2/3 of the distance.
Now, I need to subtract this value from 12 hours to find the remaining time I have left.
- 12 h - 6.89655172 h = 5.10344828 h  
Using this remaining time and my remaining distance, I can calculate my average speed.
- ? km/1 hr = 400 km/5.10344828 h 
- 5.10344828 · ? = 400 
- ? = 400/5.10344828 
- ? = 78.3783783148  
My average speed during the last third of the distance is around 78 km/h.